PCT Patent Application Number 05/084909A1 (Inventor: Nagata, Yoshihiko; Published: 2005-09-15) appears to disclose a mold-support device for an injection-molding system.
U.S. Design Pat. No. 472,566 (Inventor: Okada, Norihito; Published: 2003-04-01) appears to disclose a platen of a molding system.
U.S. Pat. No. 6,984,121 (Inventor: Fischbach, Gunther et al; Published: 2006-01-10) appears to disclose a platen for an injection-molding machine.
U.S. Pat. No. 6,746,232 (Inventor: Becker et al; Published: 2004-06-08) appears to disclose a platen for an injection-molding machine, in which the platen includes flexible connectors at the corners to support bushes for tie bars.
U.S. Pat. No. 6,439,876 (Inventor: Glaesener, Pierre; Published 2002-08-27; Assignee: Husky Injection Molding Systems Limited) appears to disclose a mold-support platen of a molding system.
FIGS. 1A, 1B and 1C provide views of a platen 1 according to U.S. Pat. No. 6,439,876. The top-most image is a perspective-frontal view of the platen 1. The lower-most image is an end view of the platen 1. The image between the top-most and bottom-most images is a perspective-rearward view of the platen 1. The platen 1 includes a mold-support face 4 (hereafter referred to as the “face 4”). A peripheral wall 30 extends rearward of the face 4. The face 4 includes force-receiving faces 24 extending posterior of the face 4. The face 4 has clearances for tie bars 18 at the four corners of the face 4. Walls 34 extend rearward from the face 4.
FIGS. 2A and 2B are cross-sectional views of the platen 1 of FIG. 1A. The platen 1 is used in a molding system 2. The face 4 supports a mold 8 that includes mold halves. One of the mold halves is attachable to the face 4, while the other of the mold halves is attachable to a stationary platen 10. An injection unit 12 is used to process a molding material that is to be injected into a cavity defined by the mold 8. A clamping block 14 includes clamping mechanisms used to actuatably move a clamp column 16 attached to the platen 1 so that the platen 1 is movable away from and toward the stationary platen 10 so that the mold 8 may be closed and opened. The clamping block 14 is known to those skilled in the art of molding machinery and thus the clamping block 14 will not be discussed. The tie bars 18 attach the stationary platen 10 with the clamping block 14 so that a clamping force may be applied to the mold 8. The force-receiving face 24 is offset rearward from the face 4 so that a clamping force that is applied to the platen 1 is divergently transmitted from the force-receiving face 24 across the face 4. The force-receiving face 24 is smaller than the face 4. A border 26 surrounds the face 4. The width of the border 26 extends from the outer edge of the face 4 toward the outer edge of the force-receiving face 24. For some implementations, the footprint of the force-receiving face 24 is approximately equal to the footprint of the clamp column 16. However, the footprint of the force-receiving face 24 is depicted as larger than the footprint of the clamp column 16.
The clamp column 16 is a force-acting area or structure in that the clamping force is transmitted through the clamp column 16 to the mold 8. The footprint of the mold 8 is larger than the footprint of the clamp column 16 such that a portion of the mold 8 extends from a central portion of the face 4 and into the border 26. Upon application of a clamping force, the border 26 becomes warped (that is, the border 26 is bend toward the clamping block 14), and as a result the portion of the mold 8 that is connected to the border 26 will open and thus it will experience inadvertent flashing during injection of the molding material into the mold 8. This is a problematic condition.
FIG. 2B is a side view of the platen 1 of FIG. 2A in which a clamping force is applied to the mold 8. The clamping force is generated by the clamping block 14. The generated clamping force includes a first-force component 20 and a second-force component 22 that are equal to each other in magnitude but applied opposite to each other across the mold 8. The first-force component 20 is transmitted to the mold 8 along a pathway that extends from the clamping block 14 through the tie bars 18 into the stationary platen 10 and to the mold 8. The second-force component 22 is transmitted along a pathway that extends from the clamping block 14 through the clamp column 16 and into the platen 1 and then to the mold 8.
A Central portion of the face 4 is positioned within the footprint of the clamp column 16, and the central portion of the face 4 does not warp or bend when the second force-component 22 is applied to the mold 8. However, the force component 22 is transmitted divergently across the border 26, and as such (disadvantageously) the border 26 becomes warped by the force component 22. When the border 26 becomes warped, the mold 8 will flash (that is, molding material will inadvertently leak out from the mold 8 during injection of the molding material). The border 26 bends back toward the clamping block 14 (because the force component 22 is unequally distributed (or diluted) across the border 26). Since not as much of the force component 22 reaches the border 26, the border 26 does not get pushed as much as, for example, the central portion of the face 4.
Therefore, in order to counter act backward bending of the border 26, persons skilled in the art may consider the following option: apply a higher clamp force (tonnage) via the column 16 in order to keep the mold-support faces of the platen 1, 10 parallel with each other. However, a negative consequence may occur, amongst other things, as a result of the foregoing option (which may not completely motivate the person skilled in the art away from the option): if the clamping force is increased, more energy would be required to generate and apply the clamping force to the platen 1 and thus the molding system 2 may be more expensive to operate.